1. Field of Invention
The present invention relates to a water treatment device, and more particularly to a rotatable water treatment device that reduces mud adherence.
2. Description of Related Art
In the conventional sewage recycle treatment, adopting the membrane filtering method is a critical procedure. But the concentration polarization and the membrane fouling of this method usually slow down the filtering liquid speed. Thus, the filtering efficiency of the membrane also decreases.
Refer to FIG. 1. The conventional water-filtering device includes a hollow cylinder 310, a covering 320, an upper laminate 330, a bottom laminate 340, a conduit 350 and a plurality of filtering units 360. The hollow cylinder 300 has a space that contains the upper laminate 330 and the bottom laminate 340. The conduit 350 is connected from the center of the upper laminate 330 to the center of the bottom laminate 340. The filtering units 360 surround the conduit 350 in the form of stacked layers. The hollow cylinder 310 has a water inlet 312 and a water outlet 314 defined beneath and connected with the space. Furthermore, each filtering unit 360 includes a filtering membrane 362, a water-conducting disc 364 and an actinoid vane 366. The filtering membrane 362 is in the form of a flat bag. The water-conducting disc 364 is used to fix and position the filtering membranes 362. The actinoid vane 366 is fixed between the adjacent filtering membranes 362.
During the water-filtering process, the water is pumped into the hollow cylinder 310 through the water inlet 312 and passes through the filtering units 360 from the bottom to the top. The water flows into the filtering membranes 362 through tiny holes of the filtering membranes 362 because of the water pressure, and then flows into the conduit 350. The water then flows through the conduit 350 and is directed to the water outlet of the hollow cylinder 310 to output the filtered liquid.
When the filtering speed is gradually slowed down, the spout-brush method prevents concentration polarization and membrane fouling. The spout-brush method injects water into the conduit and spouts high-pressure water to clean the filtering membrane surface of the filtering units 360 directly. The actinoid vane 366 is also forced to rotate and scrape the dirt attached on the filtering membrane surface.
Although the previous water-filtering device can achieve the desirable objects, the filtering membranes are made of soft material such that the fluid channel between the corresponding filtering membranes is lessened. In this way, the water generation speed is slowed down. Additionally, each vane 366 is stacked between the adjacent filtering membranes 362 and depends on the high-pressure water to rotate and to scrape the dirt attached on the filtering membrane surface. If the dirt or the mud is so numerous that the vane is not capable of rotating normally, the cleaning efficiency of the water treatment is reduced.
Because the vane is exposed in the raw water, the imperceptible mud is easily attached to the surface of the actinoid vane 366 so that the actinoid vane 366 is difficult to clean. Hence, the actinoid vane 366 must be replaced after a constant period.
Consequently, the conventional water-filtering device has the following drawbacks:
1. Because the filtering membranes are made of soft material, the fluid channel between the corresponding filtering membranes decreases when the filtering membranes are pressed by the water. Therefore, the water generation cannot be enhanced.
2. The attached mud between the actinoid vane and the water-conducting disc affects the rotating efficiency of the actinoid vane. Thus, the turbulent flow effect and the cleaning efficiency are decreased.
3. The imperceptible mud is easily attached to the surface of the vane, resulting is that the vane is difficult to clean. Thus, the vane must be replaced frequently. Hence, the cost is raised and the using period is reduced.
4. Not only the vane but also the filtering membrane must be replaced. The actinoid vane and the filtering membrane are replaced individually because they are separate components. Thus, replacing both the actinoid vane and the filtering membrane is time-consuming, inconvenient and high expense.